PP - If you are on an ADSL connection via your 'phone line then you are unlikely to ever achieve anywhere near 8.0mbps. In these rural parts we have been told that 1.5mbps is a good day and 750 to 850kbps is about average due to the fact that the telephone wiring is old and not of sufficient capacity to give much more.
If you are on cable then you really do have a problem as that should deliver what it says on the box.
Cheers,
PB.